1. Field of the Invention
This invention relates to a method of packaging a strip of material. The method relates to material for use in cutting into sheet elements arranged end to end.
2. Description of Related Art
Strips of material are used for manufacture of diapers and other absorbent products. The strips are cut on the manufacturing line at longitudinally spaced transverse cut lines to divide the strip into individual sheet elements each used in the manufacture of a respective absorbent product. Generally these strips are also die cut to provide different widths for shaping of the products to better match the body of the user and for better aesthetics. Most current processes of this type die cut the elements from a single strip of the material having a width at least equal to the maximum required width and discard the waste at the sides formed by cutting away the side portions to the narrower scalloped width. Attempts are made to recycle the waste portions, generally by grinding and returning the materials to the strip manufacturer. However, recent developments have increased the complexity of the materials thus increasing the cost and making recycling more difficult. There is therefore industry pressure to reduce the amount of waste.
It has been previously proposed to longitudinally slit a web of the required materials into a plurality of side by side strips which have varying width. The shaping is arranged so that the strips have the wider portion of one adjacent to the narrower portion of the next and vice-versa. This eliminates or at least reduces the amount of waste relative to an arrangement in which all sheet elements are cut individually from a respective strip of constant width.
However, the packaging of such continuous strips is problematic as the strip of elements are of varied width so that the location of the side edges varies. One proposal is to form the strip into a single pancake roll or pad which is wound spirally. Another proposal is to wind the strip in a traverse package. Neither package structure is stable since the side edges of one wound layer do not directly overlie the side edges of the next leaving overhanging portions and feathered edges.
Previously, packages of a continuous strip of material have been formed using a technique known as xe2x80x9cfestooningxe2x80x9d in which the strip is laid back and forth in a series of strip portions, with each portion being arranged relative to the next about a line generally transverse to the strip. The technique of festooning has been available for many years and is used in packaging many different types of materials but particularly material of a fibrous nature such as fabric, non-woven strips and the like. In this technique, the strip is conventionally guided into a receptacle such as a cardboard box while a first reciprocating movement causes portions of the strip to be laid across the receptacle and laid back and forth and a second reciprocating movement causes the positions of the portions to be traversed relative to the receptacle transversely to the portions. The strip portions thus partially overlay the adjacent strip portion in accordance with the dual reciprocating movements. Normally, the receptacle comprises a rigid rectangular container, at least partly of cardboard having a base and four upstanding sides. The sides prevent the loosely laid strips from sliding from the pile.
Festooning can be used for packaging strips of varying width, but this technique has significant disadvantages which inhibit the effectiveness of the product when removed and processed. In particular, fold lines created by laying the strip portions, which cannot be avoided, interfere with the absorbency or other performance of the material when such fold lines occur at a central area of the sheet element.
One aspect of the embodiments of this invention is to provide an improved package structure of a strip of material for cutting transversely of the sheet into a plurality of separate sheet elements arranged end to end.
According to one aspect of the invention there is provided a method of forming a package of a strip of sheet material comprising:
providing a strip of material having a first side edge, a second side edge defining a width therebetween, a first surface and a second surface, the strip having a width across the strip which varies along the length of the strip such that the width of the strip varies from areas of minimum width to areas of maximum width;
forming a plurality of stacks of the strip by folding the strip in each stack repeatedly back and forth to form a plurality of folded strip portions of the strip, with each folded strip portion of the strip being folded relative to one next adjacent folded strip portion about a first fold line transverse to the strip and relative to a second next adjacent folded strip portion about a second fold line transverse to the strip and spaced from the first fold line;
arranging the folded strip portions of each stack to form a plurality of first fold lines arranged at one of two opposed ends of the stack and a plurality of second fold lines arranged at the other of the ends of the stack;
arranging the folded strip portions of each stack superimposed each on the previous strip portion with the side edges thereof directly aligned such that the areas of maximum width of the folded strip portions are directly superimposed and areas of minimum width of the folded strip portions are directly superimposed and such that the fold lines of each stack at each end of the stack are aligned so as to lie in common planes;
and arranging the stacks side by side in a common package structure
with the side edges of the folded strip portions of one stack adjacent to the side edges of the folded strip portions of a next adjacent stack,
with alternate stacks having the fold lines thereof offset from the fold lines of next adjacent stacks in a direction longitudinal to the strip portions of the stacks,
and with the stacks being nested such that the areas of minimum width of each stack lie alongside areas of maximum width of the next adjacent stack.
Preferably the fold lines of alternate stacks lie in common planes.
Preferably, the strip in each stack is continuous or designed to be integrally connected, at least to function as one piece, from an end connecting portion at one end of the stack to an end connecting portion at an opposed end of the stack. Each stack can include one end connecting portion of the strip from each stack for splicing to an end connecting portion of the strip of the next adjacent stack by a splice connecting portion of the strip to form a strip that is continuous along its length through the package.
Preferably, the stacks are substantially upright with a bottom and a top, two sides parallel to the edges of the strips of the stacks and two ends containing the fold lines of the stacks. The end connecting portion of the bottom of a stack can be connected to the end connecting portion of the top of a next adjacent stack to form the splice connecting portion that extends along one end of the stack.
Preferably, the package is compressed downwardly so as to decrease the height of the stacks from a rest height to a compressed height. The package can be engaged by packaging material which maintains the compression. Preferably, the compression is sufficient to reduce the thickness of each strip portion of said stacks. In the preferred compressed embodiment, the strip is fibrous.
The package can be wrapped by a flexible packaging material from which air is withdrawn and which is sealed against ingress of air. The flexible packaging material can be conventional shrink wrap, fabric, paper or a closed bag.
In one embodiment, the method includes applying to the strip of each stack a series of machine readable markings each at a longitudinal location on the strip arranged to identify a longitudinal location of a respective one of the fold lines. The method includes unfolding the strip, scanning the unfolded strip to locate the machine readable markings, and cutting the unfolded strip by using the machine readable markings to locate cut lines transverse to the strip at, adjacent to or at a predetermined distance from the fold lines.
According to a second aspect of the present invention there is provided a method of forming a package of a strip of sheet material comprising:
providing a strip of material having a first side edge, a second side edge defining a width therebetween, a first surface and a second surface, the strip having a width across the strip which varies along the length of the strip such that the width of the strip varies from areas of minimum width to areas of maximum width;
forming a plurality of stacks of the strip by folding the strip in each stack repeatedly back and forth to form a plurality of folded strip portions of the strip, with each folded strip portion of the strip being folded relative to one next adjacent folded strip portion about a first fold line transverse to the strip and relative to a second next adjacent folded strip portion about a second fold line transverse to the strip and spaced from the first fold line;
arranging the folded strip portions of each stack to form a plurality of first fold lines arranged at one of two opposed ends of the stack and a plurality of second fold lines arranged at the other of the ends of the stack;
arranging the folded strip portions of each stack superimposed each on the previous strip portion with the side edges thereof directly aligned such that the areas of maximum width of the folded strip portions are superimposed and areas of minimum width of the folded strip portions are superimposed and such that the fold lines of each stack at each end of the stack are aligned so as to lie in common planes;
and arranging the stacks in a common package structure with the stacks side by side such that the ends of the stacks lie at respective ends of the package,
with the side edges of the folded strip portions of one stack adjacent to the side edges of the folded strip portions of a next adjacent stack,
with the fold lines at one end of the stacks of all the stacks being aligned so as to lie in a first common plane at one end of the package and the fold lines at the other end of the stacks of all the stacks being aligned so as to lie in a second common plane at the other end of the package,
and with the stacks being nested such that the areas of minimum width of each stack lie alongside areas of maximum width of the next adjacent stack.